title: XPC Lys939Gln polymorphism, smoking and risk of sporadic colorectal cancer among Malaysians.
abstract: OBJECTIVE
  To investigate the risk association of xeroderma pigmentosum group C (XPC) Lys939Gln polymorphism alone and in combination with cigarette smoking on colorectal cancer (CRC) predisposition.
  
  
  METHODS
  Peripheral blood samples of 510 study subjects (255 CRC patients, 255 controls)were collected. DNA was extracted and genotyping was performed using polymerase chain reaction-restriction fragment length polymorphism. The association between polymorphic genotype and CRC predisposition was determined using the OR and 95%CI.
  
  
  RESULTS
  The frequency of the homozygous variant (Gln/Gln) genotype was significantly higher in cases compared with controls (16.0% vs 10.2%, P = 0.049). The Gln/Gln genotype of XPC showed a significantly higher association with the risk of CRC (OR = 1.884; 95%CI: 1.082-3.277; P = 0.025). In the case of allele frequencies, variant allele C was associated with a significantly increased risk of CRC (OR = 1.375; 95%CI: 1.050-1.802; P = 0.020). Moreover, the risk was markedly higher for those who were carriers of the Gln/Gln variant genotype and were also cigarette smokers (OR = 3.409; 95%CI: 1.061-10.949; P = 0.032).
  
  
  CONCLUSIONS
  The XPC Gln/Gln genotype alone and in combination with smoking increases the risk of CRC among Malaysians.
authors.affiliation: Human Genome Centre, School of Medical Sciences,Universiti Sains Malaysia, Health Campus,16150 Kubang Kerian, Kelantan, Malaysia.
authors.forename: Abdul Aziz
authors.initials: AA
authors.lastname: Ahmad Aizat
authors.forename: Mohd Shahpudin
authors.initials: MS
authors.lastname: Siti Nurfatimah
authors.forename: Mustapha Mohd
authors.initials: MM
authors.lastname: Aminudin
authors.forename: Ravindran
authors.initials: R
authors.lastname: Ankathil
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D044466:Asian People / Q000235:genetics*; D016022:Case-Control Studies; D016009:Chi-Square Distribution; D015179:Colorectal Neoplasms / Q000208:ethnology / Q000235:genetics*; D004268:DNA-Binding Proteins / Q000235:genetics*; D005260:Female; D005787:Gene Frequency; D020022:Genetic Predisposition to Disease; D006579:Heterozygote; D006720:Homozygote; D006801:Humans; D016015:Logistic Models; D008296:Malaysia / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D016017:Odds Ratio; D010641:Phenotype; D020641:Polymorphism, Single Nucleotide; D018570:Risk Assessment; D012307:Risk Factors; D012907:Smoking / Q000009:adverse effects* / Q000208:ethnology
chemical_list: D004268:DNA-Binding Proteins; C086984:XPC protein, human
keywords: Cigarette smoking; Colorectal cancer; DNA repair; Susceptibility risk; Xeroderma pigmentosum group C Lys939Gln polymorphism